How fast could someone (maximum velocity) be with almost exclusively slow-twitch fibers?

Scientistic wrote:

Slow twitch fibers don't even have the capacity to contract fast enough to run. Its thought that what slow twitch fibers do in Distance and Middle Distance runs is store glycogen for working TypeIIA fibers, OR remove lactate from working Type IIA fibers.

If you were composed of entirely slow twitch fibers you would be completely nonathletic. You might be able to walk for extended periods but you would probably have some sort of muscular dystrophy...

I do not think this is correct. Why would st fibers removing lactate from ft fibers be beneficial when ft fibers use lactate as an energy source?

Regarding the second statement, the research I have seen states the opposite: the least fit of people and those with muscular disorders tend to have the highest proportion of purely ft type ii fibers. Even sprint and resistance training tend to cause shifts towards more oxidative characteristics.

Scientistic wrote:

so 90% of all athletes of any event have the RR or RX profile for the ACTN3 (fast twitch) gene.

Getting Gene tested then is almost a waste of money, as nearly every random person walking on the street is encoded the same elite athletes. This shows how truly important training and dedication to training really is.

There is no 'sports gene'. There is no elite genetic profile if 90% of the population has it. Thats scientific garbage the same as muscle biopsies that counted two colors in fibers under a microscope Its in nearly everyone. Most people are fast twitch dominant, and fast twitch fibers do most of the work in running.

i am not a scientist and my questions are:

- if there´s no ´sports gene´: how to explain the training limits of low mileage/high mileage guys, the differences of the recovery time needed?

- if there´s no ´sports gene´: how to explain that some runners can run fast after a short time of training, while others, who look quite similiar like the fast guys, train like mad for years, but never run really fast?

- is it just a matter of training that has to be put in?

probably out of context because it is a mistake.

recruitment patterns are far more complex and also duration dependent.

Scientistic wrote:

So give a complete picture in your 'rebuttal' and stop counting the red fibers after you butchered someone's leg for a couple bucks.

???

You are trolling on mushrooms or something. All I said was, back up your way-out assertions about the role of type 1 muscle fibers.

1/10 for getting a few responses, but fooling nobody.

Cool, then refute it and make a logical argument about why observed data isn't accurate.

You're talking about non fit people with no gene or muscle disorders who are sedentary (often by choice).

That is quite distinct from individuals with muscular dystrophy and can't even stand or walk.

Basically someone who is pure slow twitch would never be able to get in shape, while even a sedentary couch potato would be with hard work.

Bad Wigins wrote:

???

You are trolling on mushrooms or something. All I said was, back up your way-out assertions about the role of type 1 muscle fibers.

1/10 for getting a few responses, but fooling nobody.

Cool moron go write a book. Did you even list the reasons or explain your rebuttal? No you just said it was wrong. Well I'm just saying you're wrong.

I like this question very much. I have always wondered what the proportion of fast twitch and slow twitch fibers is in Michael Phelps. He supposedly had a blood lactate of under 6mmol after a world record 100m butterfly race where everyone else ever tested had 15-20mmol or more under the same conditions.

Epo

SlowFatMaster wrote:

I like this question very much. I have always wondered what the proportion of fast twitch and slow twitch fibers is in Michael Phelps. He supposedly had a blood lactate of under 6mmol after a world record 100m butterfly race where everyone else ever tested had 15-20mmol or more under the same conditions.

Your argument talking about cadence doesn't make any sense and it took me a while to even work out what it was you were trying to say. Power and speed are not simple functions of cadence. Cadence is what you get when you sum up all the muscle fibres that are contracting and at what rates and multiply it by a few limbs. Cadence is a 'result', not a 'cause'.

Muscle contraction is a more involved process whereby change in length is a function of the total number of muscle fibres that contract, and power is a function of the rate at which they contract (where rate is the sum over all fibres). These processes are controlled by motor units, which determine which fibres contract and when.

Also, I'm afraid you don't get to say a bunch of stuff and it automatically become true until someone refutes it. If you make a claim then the onus is on you to support it with evidence.

Again I'd really like to see your source on why "it is thought" that the role of type I fibres is little more than storing glycogen for type IIa fibres (I won't argue about the transport of lactate between cells as that is an accepted model). Thanks.

Gary Tuttle (2nd place Boston, former AR holder in 3 events, 28:26 at 36 years old) tested at 98% slow twitch in his gastrocnemius (Fink et al, 1977). That's the same study where the aforementioned Galloway was tested at 96% (http://sportsillustrated.cnn.com/vault/article/magazine/MAG1091057/2/index.htm ... "while Galloway, calling on but 4% sprint fibers, is dangerous over the last lap.")

Tuttle:

http://www.ujenafitclub.com/ninter.php/22

mile: 4:03.8

10000m: 28:26

marathon: 2:15:15

Ummm. He asked you to provide sources. He didn't provide a rebuttal or say you were right or wrong. Providing external references tells us you are not just making it up.The one source you provided didn't talk about muscle fibers at all, but rather two genes. Nothing in the link talks about slow twitch muscles indirectly supporting fast twitch in any way.

Scientistic wrote:

Bad Wigins wrote:

???

You are trolling on mushrooms or something. All I said was, back up your way-out assertions about the role of type 1 muscle fibers.

1/10 for getting a few responses, but fooling nobody.

Cool moron go write a book. Did you even list the reasons or explain your rebuttal? No you just said it was wrong. Well I'm just saying you're wrong.

Measuring the calf muscle is dumb.

The bulk of propulsion in running is the hams and glutes. Those muscle groups have much more fast twitch than the calf muscle.

In addition determination of twitch is done by, counting fibers in those old tests from biopsies, not actual chemical analysis of the neuron head.

Still no link?

There is plenty of time for the slow twitch fibers to contract, even during sprinting.

The foot may typically be in contact with the ground for 60 to 100 milliseconds during sprinting, and 120-200 milliseconds for elite mid-d and distance runners.

Slow twitch muscles can contract maximally in about 100 milliseconds and relax completely in about 160 millisecond. Fast twitch muscles (that we are talking of here) can contract in about 40 milliseconds and relax completely again in about 60 milliseconds. Fast twitch muscles of the eye are considerably faster, but not really relevant in this discussion.

So you see, the slow twitch muscle can go through a complete cycle of contraction and relaxation in about 260-300 milliseconds. A sprinter (certainly not 220 strides per minute btw, that's nonsense) who is as high as about 300 strides per minute is actually only making 150 complete cycles per minute, or one cycle every 400 milliseconds.

One slow twitch contraction-relaxation cycle = roughly 300 milliseconds.

One cycle of a sprinter at 300 strides per minute = roughly 400 milliseconds.

All types of muscles fibers are contributing during a sprint, AND all types of muscles fibers are contributing during a maximal effort distance run. Sure, some fibers contribute more energy than others, but they all pitch in as often as possible.

PS - Don't fall into the trap of thinking the slow twitch muscles don't have time to contract just because the foot is on the ground during sprinting for a shorter time than it takes for a complete contraction; they start firing again near the end of the swing-phase forward just before the foot extends back down to the ground.

This definitely confirms you're trolling. Are you really that bored?